myBatis实例
一.搭建环境,
建立数据库
1 CREATE TABLE user( 2 id int(11) not NULL AUTO_INCREMENT, 3 userName varchar(50) DEFAULT NULL, 4 userAge int(11) DEFAULT NULL, 5 userAddress varchar(200) DEFAULT NULL, 6 PRIMARY KEY(id) 7 )ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
建立一个myBatis的java项目(不需要web项目)
然后倒入jar包
建总配置文件:
在src下建configration包.在建Configurations.xml文件
代码如下:
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE configuration PUBLIC " -//mybatis.org//DTD Config 3.0//EN" 3 "http://mybatis.org/dtd/mybatis-3-config.dtd"> 4 <configuration> 5 <typeAliases> 6 <typeAlias type="com.user.User" alias="User"/> 7 </typeAliases> 8 <environments default="development"> 9 <environment id="development"> 10 <transactionManager type="JDBC" /> 11 <dataSource type="POOLED"> 12 <property name="driver" value="com.mysql.jdbc.Driver"/> 13 <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis"/> 14 <property name="username" value="root"/> 15 <property name="password" value="123"/> 16 </dataSource> 17 </environment> 18 </environments> 19 20 <mappers> 21 <mapper resource="configration/User.xml"/>
</mappers> 24 </configuration>
建user的实体类和映射文件:
com.user.User代码:
1 package com.user; 2 3 public class User { 4 private int id; 5 private String userName; 6 private String userAge; 7 private String userAddress; 8 public int getId() { 9 return id; 10 } 11 public void setId(int id) { 12 this.id = id; 13 } 14 public String getUserName() { 15 return userName; 16 } 17 public void setUserName(String userName) { 18 this.userName = userName; 19 } 20 public String getUserAge() { 21 return userAge; 22 } 23 public void setUserAge(String userAge) { 24 this.userAge = userAge; 25 } 26 public String getUserAddress() { 27 return userAddress; 28 } 29 public void setUserAddress(String userAddress) { 30 this.userAddress = userAddress; 31 } 32 33 }
configration包下见User.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 3 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 4 5 <mapper namespace="User"> 6 <select id="selectUserById" parameterType="int" resultType="User"> 7 select * from user where id=#{id} 8 </select> 9 <select id="selectUserList" parameterType="int" resultType="User"> 10 select * from user 11 </select> 12 </mapper>
建测试类
1 package test; 2 3 import java.io.Reader; 4 import java.util.List; 5 6 import org.apache.ibatis.io.Resources; 7 import org.apache.ibatis.session.SqlSession; 8 import org.apache.ibatis.session.SqlSessionFactory; 9 import org.apache.ibatis.session.SqlSessionFactoryBuilder; 10 11 import com.user.User; 12 13 public class Test { 14 private static SqlSessionFactory sqlSessionFactory; 15 private static Reader reader; 16 17 static { 18 try { 19 reader = Resources.getResourceAsReader("configration/Configurations.xml"); 20 sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); 21 } catch (Exception e) { 22 e.printStackTrace(); 23 } 24 } 25 public static void main(String[] args) { 26 SqlSession session = sqlSessionFactory.openSession(); 27 try { 28 //User user = (User) session.selectOne("User.selectUserById", 2); 29 List<User> list=session.selectList("User.selectUserList"); 30 for(User user:list){ 31 System.out.println("姓名:"+user.getUserName()); 32 System.out.println("年龄"+user.getUserAge()); 33 System.out.println("地址:"+user.getUserAddress()); 34 System.out.println("-----------------------------------------------------------"); 35 } 36 37 } catch (Exception e) { 38 System.out.println("出现异常了....."); 39 e.printStackTrace(); 40 } finally { 41 session.close(); 42 } 43 } 44 }
当你查看到从数据库中读取的数据时,说明环境搭建完毕了
二.用接口的方式实现编程.
建立IUserOperation.java
1 package inter; 2 3 import java.util.List; 4 5 import com.user.User; 6 7 public interface IUserOperation { 8 public User selectUserById(int id); 9 public List<User> selectUserList(); 10 }
建立IUser.xml.
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 3 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 4 5 <mapper namespace="inter.IUserOperation"> 6 <select id="selectUserById" parameterType="int" resultType="User"> 7 select * from user where id=#{id} 8 </select> 9 <select id="selectUserList" resultType="User"> 10 select * from user 11 </select> 12 </mapper>
注意这个地方的namspace就不可以随意取名字了.必须是实现接口的地址.
在总配置文件中mappers添加一条xml:<mapper resource="configration/IUser.xml"/>
添加测试类:
1 package test; 2 3 import inter.IUserOperation; 4 5 import java.io.Reader; 6 import java.util.List; 7 8 import org.apache.ibatis.io.Resources; 9 import org.apache.ibatis.session.SqlSession; 10 import org.apache.ibatis.session.SqlSessionFactory; 11 import org.apache.ibatis.session.SqlSessionFactoryBuilder; 12 13 import com.user.User; 14 15 /** 16 * 以接口的方式编程 17 * 如果以这种方式的话,那么对应的sql的xml配置文件中的namespace必须是实现接口的具体地址 18 */ 19 public class TestInterface { 20 private static SqlSessionFactory sqlSessionFactory; 21 private static Reader reader; 22 23 static { 24 try { 25 reader = Resources.getResourceAsReader("configration/Configurations.xml"); 26 sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); 27 } catch (Exception e) { 28 e.printStackTrace(); 29 } 30 } 31 public static void main(String[] args) { 32 SqlSession session = sqlSessionFactory.openSession(); 33 try { 34 IUserOperation userOperation=session.getMapper(IUserOperation.class); 35 /*User user=userOperation.selectUserById(3); 36 System.out.println(user.getUserAddress()); 37 System.out.println(user.getUserName());*/ 38 39 List<User> list=userOperation.selectUserList(); 40 for(User user:list){ 41 System.out.println("姓名:"+user.getUserName()); 42 System.out.println("年龄:"+user.getUserAge()); 43 System.out.println("地址:"+user.getUserAddress()); 44 System.out.println("--------------------------------"); 45 } 46 47 48 } catch (Exception e) { 49 System.out.println("出现异常了....."); 50 e.printStackTrace(); 51 } finally { 52 session.close(); 53 } 54 } 55 }
三,使用myBatis完成增删改查.
重新修改以下文件.
IUser.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 3 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 4 5 <mapper namespace="inter.IUserOperation"> 6 <!-- 返回list数据集时使用的返回map --> 7 <resultMap type="User" id="resultListUserMap"> 8 <id column="id" property="id" /> 9 <result column="userName" property="userName"/> 10 <result column="userAge" property="userAge"/> 11 <result column="userAddress" property="userAddress"/> 12 </resultMap> 13 <select id="selectUserById" parameterType="int" resultType="User"> 14 select * from user where id=#{id} 15 </select> 16 <select id="selectUsers" parameterType="String" resultMap="resultListUserMap"> 17 select * from user where userName like #{userName} 18 </select> 19 <!-- 20 执行增加操作的SQL语句.id和parameterType分别与IUserOperation接口中的 21 adUser方法的名字和参数类型一致.以#{name}的形式引用User参数的name属性. 22 myBatis将使用反射读取User参数的此属性.#{name}中name大小写敏感. 23 seGeneratedKeys设置为true,表明要myBatis获取自由数据库自动生成的主键; 24 keyProperty="id"指定把获取到的主键值注入到User的id属性 25 --> 26 <insert id="addUser" parameterType="User" useGeneratedKeys="true" keyProperty="id"> 27 insert into user(userName,userAge,userAddress) 28 values(#{userName},#{userAge},#{userAddress}); 29 </insert> 30 31 <update id="updateUser" parameterType="User"> 32 update user set userName=#{userName},userAge=#{userAge},userAddress=#{userAddress} 33 where id=#{id} 34 </update> 35 36 <delete id="deleteUser" parameterType="int"> 37 delete from user where id=#{id} 38 </delete> 39 40 </mapper>
IUserOperation.java
1 package inter; 2 3 import java.util.List; 4 5 import com.user.User; 6 7 public interface IUserOperation { 8 public User selectUserById(int id); 9 public List<User> selectUsers(String userName); 10 public void addUser(User user); 11 public void updateUser(User user); 12 public void deleteUser(int id); 13 }
Test1.java
1 package test; 2 3 import inter.IUserOperation; 4 5 import java.io.Reader; 6 import java.util.List; 7 8 import org.apache.ibatis.io.Resources; 9 import org.apache.ibatis.session.SqlSession; 10 import org.apache.ibatis.session.SqlSessionFactory; 11 import org.apache.ibatis.session.SqlSessionFactoryBuilder; 12 13 import com.user.User; 14 15 public class Test1 { 16 private static SqlSessionFactory sqlSessionFactory; 17 private static Reader reader; 18 static { 19 try { 20 reader = Resources 21 .getResourceAsReader("configration/Configurations.xml"); 22 sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); 23 } catch (Exception e) { 24 e.printStackTrace(); 25 } 26 } 27 public void getUserList(String userName){ 28 SqlSession session=sqlSessionFactory.openSession(); 29 try { 30 IUserOperation userOperation=session.getMapper(IUserOperation.class); 31 List<User> users=userOperation.selectUsers(userName); 32 for(User user:users){ 33 System.out.println("id:"+user.getId()); 34 System.out.println("name:"+user.getUserName()); 35 System.out.println("age:"+user.getUserAge()); 36 System.out.println("address:"+user.getUserAddress()); 37 System.out.println("-----------------"); 38 } 39 } catch (Exception e) { 40 System.out.println("查询出错了......"); 41 }finally{ 42 session.close(); 43 } 44 45 } 46 47 /** 48 * 添加数据,必须提交事务,否则不会写入dao数据库 49 * @param args 50 */ 51 public void addUser(){ 52 User user=new User(); 53 user.setUserAddress("安徽,舒城"); 54 user.setUserAge(26); 55 user.setUserName("思思博士"); 56 SqlSession session=sqlSessionFactory.openSession(); 57 try { 58 IUserOperation userOperation=session.getMapper(IUserOperation.class); 59 userOperation.addUser(user); 60 session.commit(); 61 System.out.println("当前增加的id为:"+user.getId()); 62 } catch (Exception e) { 63 System.out.println("添加出现异常啦........"); 64 }finally{ 65 session.close(); 66 } 67 } 68 69 /** 70 * 71 * @param args 72 */ 73 public void updateUser(){ 74 User user=new User(); 75 user.setUserAddress("安徽,舒城,千人桥镇"); 76 user.setUserAge(260); 77 user.setUserName("思思博士"); 78 user.setId(4); 79 SqlSession session=sqlSessionFactory.openSession(); 80 try { 81 IUserOperation userOperation=session.getMapper(IUserOperation.class); 82 userOperation.updateUser(user); 83 session.commit(); 84 //System.out.println("当前增加的id为:"+user.getId()); 85 } catch (Exception e) { 86 System.out.println("更新出现异常啦........"); 87 }finally{ 88 session.close(); 89 } 90 } 91 92 /** 93 * 删除数据 94 * @param args 95 */ 96 public void deleteUser(int id){ 97 SqlSession session=sqlSessionFactory.openSession(); 98 try { 99 IUserOperation userOperation=session.getMapper(IUserOperation.class); 100 userOperation.deleteUser(id); 101 session.commit(); 102 System.out.println("数据删除成功"); 103 } catch (Exception e) { 104 System.out.println("数据删除失败啦....."); 105 } 106 finally{ 107 session.close(); 108 } 109 } 110 111 112 public static void main(String[] args) { 113 Test1 test1=new Test1(); 114 //查询列表 115 test1.getUserList("%"); 116 //test1.addUser();//添加数据 117 //test1.updateUser();//更新数据 118 //test1.deleteUser(3);//删除数据 119 } 120 }
四.联合查询:
IJoinUser.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 3 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 4 5 <mapper namespace="inter.IUserJoinOperation"> 6 <resultMap type="User" id="resultListUserMapss"> 7 <id column="id" property="id" /> 8 <result column="userName" property="userName"/> 9 <result column="userAge" property="userAge"/> 10 <result column="userAddress" property="userAddress"/> 11 </resultMap> 12 <!-- User联合文章进行查询方法之一的配置(多对一的方式) --> 13 <resultMap type="News" id="resultUserNewsListMap"> 14 <id property="id" column="Id" /> 15 <result property="title" column="title" /> 16 <result property="content" column="content" /> 17 <association property="user" javaType="User"> 18 <id property="id" column="id" /> 19 <result property="userName" column="userName"/> 20 <result property="userAddress" column="userAddress"/> 21 </association> 22 </resultMap> 23 24 <select id="getUserNewsList" parameterType="int" resultMap="resultUserNewsListMap"> 25 select user.id,user.userName,user.userAge,user.userAddress, 26 news.id,news.userId,news.title,news.content 27 from user,news 28 where user.id=news.userId and user.id=#{id} 29 </select> 30 31 </mapper>
IUserOperation.java
1 package inter; 2 3 import java.util.List; 4 5 import com.user.News; 6 7 public interface IUserJoinOperation { 8 public List<News> getUserNewsList(int userId); 9 }
测试类:
1 package test; 2 3 import inter.IUserJoinOperation; 4 import inter.IUserOperation; 5 6 import java.io.Reader; 7 import java.util.List; 8 9 import org.apache.ibatis.io.Resources; 10 import org.apache.ibatis.session.SqlSession; 11 import org.apache.ibatis.session.SqlSessionFactory; 12 import org.apache.ibatis.session.SqlSessionFactoryBuilder; 13 14 import com.user.News; 15 import com.user.User; 16 17 public class Test2 { 18 private static SqlSessionFactory sqlSessionFactory; 19 private static Reader reader; 20 static { 21 try { 22 reader = Resources 23 .getResourceAsReader("configration/Configurations.xml"); 24 sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); 25 } catch (Exception e) { 26 e.printStackTrace(); 27 } 28 } 29 /** 30 * 联合查询 31 * @param args 32 */ 33 public void getUserNews(int userId){ 34 SqlSession session=sqlSessionFactory.openSession(); 35 try { 36 IUserJoinOperation joinOperation=session.getMapper(IUserJoinOperation.class); 37 List<News> newsList=joinOperation.getUserNewsList(userId); 38 for(News news:newsList){ 39 System.out.println("id:"+news.getId()); 40 System.out.println("title:"+news.getTitle()); 41 System.out.println("content:"+news.getContent()); 42 System.out.println("userId:"+news.getUser().getId()); 43 System.out.println("name:"+news.getUser().getUserName()); 44 System.out.println("age:"+news.getUser().getUserAge()); 45 System.out.println("address:"+news.getUser().getUserAddress()); 46 System.out.println("------------------------------------"); 47 } 48 System.out.println("输出完毕...."); 49 } catch (Exception e) { 50 System.out.println("联合查询失败啦......."); 51 } 52 finally{ 53 session.close(); 54 } 55 } 56 57 public static void main(String[] args) { 58 Test2 test2=new Test2(); 59 //查询列表 60 test2.getUserNews(4); 61 } 62 }
其实还可以用另外一种方法:
修改IJoinUser.xml文件
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 3 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 4 5 <mapper namespace="inter.IUserJoinOperation"> 6 <resultMap type="User" id="resultListUserMapss"> 7 <id column="id" property="id" /> 8 <result column="userName" property="userName"/> 9 <result column="userAge" property="userAge"/> 10 <result column="userAddress" property="userAddress"/> 11 </resultMap> 12 <!-- User联合文章进行查询方法之一的配置(多对一的方式) --> 13 <resultMap type="News" id="resultUserNewsListMap"> 14 <id property="id" column="Id" /> 15 <result property="title" column="title" /> 16 <result property="content" column="content" /> 17 <association property="user" resultMap="resultListUserMapss" javaType="User" /> 18 <!-- <association property="user" javaType="User"> 19 <id property="id" column="id" /> 20 <result property="userName" column="userName"/> 21 <result property="userAddress" column="userAddress"/> 22 </association> --> 23 </resultMap> 24 25 <select id="getUserNewsList" parameterType="int" resultMap="resultUserNewsListMap"> 26 select user.id,user.userName,user.userAge,user.userAddress, 27 news.id,news.userId,news.title,news.content 28 from user,news 29 where user.id=news.userId and user.id=#{id} 30 </select> 31 32 </mapper>
这个地方我测试了一下,不知道为什么总是只能查出一条语句,但是sql语句直接在mysql中查询的话,可以查询多条的,哪位大神知道答案的,请告知啊.
本文非原创:
http://blog.csdn.net/techbirds_bao/article/details/9233599/